Now you [optionally] can make a major decision: break the XML round trip. EDD lets you write much more powerful structure rules than you can do in a XML DTD, e.g. you can have "ORs" (see chapter 6)These probably will partially export to SGML but never to XML. Up to you to decide. I (right now) think that in most cases one should NOT use these features if you are working in XML world, because it is nice if generated XML is valid (fits a real DTD) for various reasons not explained here.Well you might want to use automatic insertion of descendants (makes writing easier, see page 106 in the manuel). Anyhow I choose not to use all this for the moment. The extreme other option is to never work with a DTD again. You can do everything with EDD's.